Four FHIR APIs. Four ways to build them. Only some scale.
CMS-0057-F mandates four interoperability APIs with most mid-size plans still mid-vendor-selection. Here's what scaled — and what stalled — at peer plans this cycle.
The heat map — tap any cell
Four required APIs × four implementation patterns. Read for what scaled vs. what typically stalls.
| Vendor turnkey | Vendor composable | In-house build | Hybrid |
|---|
What scaled vs. what stalled
Drawn from publicly announced CMS-0057-F vendor selections, Jan–May 2026.
Scaled
- Treated CMS-0057-F as a program, not a project — one accountable exec across IT, UM, and network.
- Chose composable vendors for PA (Edifecs, Availity, MCG-integrated) and kept the rules engine in-house where UM nuance lived.
- Started PA-metrics instrumentation in Q3 2025 — so the March 31 filing was a query, not a fire drill.
Stalled
- Picked turnkey PA vendors, then found the PAS-CRD-DTR coupling didn't match LOB-specific clinical criteria — now mid-rebuild.
- Built Patient Access in-house — easy on paper, became a 9-month identity / auth / consent project.
- Treated vendor selection as a procurement decision, not an architecture decision — signed before any technical review.
The three decisions that compound
Baked in early, expensive to reverse. These set your trajectory through 2027.
Where does the PAS rules engine live?
Vendor-owned = fast launch, slow customization. In-house = slow launch, fast customization. There is no middle path that doesn't add latency.
How does Provider Access handle attribution edge cases?
Multi-payer members, mid-quarter assignment changes, network changes — your attribution math survives all three or your "real-time" API returns stale data.
What's your audit-defense story for PA decisions?
The CY2025 PA-metrics filing is publicly searchable. A slow decision time on day 1 of 2027 starts a CMS investigation cycle by day 90.
Mid-decision on any of these patterns?
I run fractional CTO engagements with mid-size MA plans (200K–2M members) on CMS-0057-F vendor selection, architecture review, and program-level delivery oversight — embedded as your technical leader through the deadline. Most engagements run 3–6 months at $30–45K/month.